Pump



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PUMP

2 Sheets-Sheet 1 Filed July 1, 1964 da-M AMA/DH A. Lfl/WML INVENTOR.

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United States ate 3,296,970 PUMP Ralph K. Londal, Detroit, Mich,assignor to Holley Carburetor Company, Warren, Mich., a corporation ofMichigan Filed July 1, 1964, Ser. No. 379,618 8 Claims. (Cl. 103-38)This invention relates generally to pumps, and more particularly to apositive displacement, constant pressure, variable stroke, eccentricdrive pump.

In the prior art constant pressure, variable stroke, eccentric drivenpumps, when the eccentric engages an abutment member of the partiallyde-stroked pump assembly, an extremely high acceleration of fuel resultsso as to cause excessive pressure pulses. These excessive pressurepulses are detrimental to the operation of systems in which the pump isemployed. Additionally the engagement of the eccentric with thepartially de-stro-ked pump assembly requires considerable force becausethe eccentric must move not only the abutment member assembly but alsothe bulk of fluid being pumped and; as a result, prior art pumpassemblies of this construction have been subject to failure after arelatively short life.

Accordingly, a general object of the invention is to provide an improvedconstant pressure, variable stroke, eccentric drive pump which issmoother in operation and less subject to failure.

A more specific object of the invention is to provide such a pumpwherein the eccentric contacts the abutment member so as to move it in ade-st-roking (suction) direction, rather than in the pumping direction;thus, the eccentric does not move the bulk of fluid being pumped, thelatter function being handled by a spring drive system.

A further object of the invention is to provide such a pump wherein anadditional shock absorbing and pressure pulse reducing feature may beincorporated, if desired.

Other objects and advantages of the invention will become apparent whenreference is made to, the following specification and the accompanyingdrawings wherein:

FIGURE 1 is a cross-sectional view of a pump embodying the invention.

FIGURE 2 is a view taken along the plane of line 2-2 of FIGURE 1, andlooking in the direction of the arrows.

FIGURE 3 is a fragmentary cross-sectional view taken along the plane ofline 3.3 of FIGURE 2 and looking in the direction of the arrows.

FIGURE 4 is a view taken along the plane of line 4-4 of FIGURE 3, andlooking in the direction of the arrows. It will be noted that FIGURES 2and 4 are unorthodox in that they are taken as if FIGURES l and 3,respectively, were side elevational views.

FIGURE 5 is an enlarged cross-sectional view of a modification of theinvention.

FIGURE 6 is a fragmentary portion of FIGURE 5, to illustrate amodification thereof.

Before discussing the drawings in detail, it should be understood thatthe various chambers of the pump shown are of a cylindricalconstruction. That is, the cross-sectional views shown by FIGURES l and5 are adequate for a complete disclosure because they are taken on asymmetrical plane.

Referring now to the drawings in greater detail, FIG- URE 1 illustratesa pump assembly 10 which includes a multiple piece, substantiallycylindrical housing 12, fastened together as by screws 13 and containingan eccentric 14. The eccentric 14 is fixedly secured to a rotatableshaft 16, as by means of a key 18 confined in grooves formed in theouter surface of the shaft and the inner surface of the eccentric. Theshaft 16 may rotate within bearings 19 secured in the housing 12. Thehousing 12 3,296,970 Federated Jan. 10, 1967 L cc further includes aplurality of chambers 20, 22, 24 and 26, which are hereinafter referredto a the central chamber, the accumulator chamber, the pumping chamberand the discharge chamber, respectively.

Pressure responsive devices, such as diaphragms 28 and 30, form movablewalls between the central chamber 20 and the accumulator chamber 22 andbetween the central chamber 20 and the pumping chamber 24, respectively.The diaphragm 28 may comprise a continuous circular piece of suitablematerial having washers 32 and 34 adjacent the opposite sides thereof,whereas the diaphragm 30 includes a central opening 36..

A piston assembly 37 is aflixed to the diaphragm 30 in the centralchamber 20. The assembly 37, better seen in FIGURES 2, 3 and 4, includesa hollow member 38 which straddles the end faces of the eccentric 14 andhas a pair of elongated openings 40 formed through the opposing sidesthereof for passage of the shaft 16, as well as a second pair ofelongated openings 41 formed perpenricular thereto. One end of thehollow member 38 includes a flange 42 which is fixedly secured to thediaphragm 30 and to a diaphragm center cover 44 by means of rivets 46.The diaphragm cover 44 includes a central opening 48 and a plurality ofradial openings 50. The flanged end 42 of the member 38 is co-unterboredto receive a check valve 52 which is urged against the counterbored seat54 by a spring 56 located between the check valve 52 and the diaphragmcover A plurality of additional openings 57 may b formed through thewall of the member 38 intermediate the openings 41 and the flange 42 forfree passage or" fluid therethrough. A hardened striker plate may bepressed into the hollow member 38 against its solid end 59.

Re erring again to FIGURE 1, the pumping chamber 24 and the dischargechamber 26 are separated by a fixed wall 68 having an opening 61 formedtherethrough, A second check valve is urged against the opening 61 by aspring 64 mounted in the discharge chamber 24.

A larger spring 66 mounted between the flange 42 of the hollow member 38and a fixed spring retainer 68 in the central chamber 20 urges thediaphragm 30 and the assembly 37 to the right in FIGURE 1, therebydecreasing the volume of the pumping chamber 24 for a purpose to bedescribed later. A still larger drive spring 70 is also mounted in thecentral chamber 20 between the cup-shaped washer 34 and a flanged seatmember 72 abutting against the solid end 59 of the hollow member 38. Aplurality of ports 76 are formed through the flanged member 72 to allowfree passage of fluid therethrough. Movement of the washer 34 to theright is limited by a mechanical stop comprising an annular abutment 7 8formed in the central chamber 20.

An inlet 80 to the central chamber 20 may be formed in a wall of thehousing 12, and an outlet 82 from the discharge chamber 26 is formed inthe end wall of the housing. A conduit, represented schematically by theline 84, communicates between the outlet 80 and the accumulator chamber22. Another conduit 86 may branch off the conduit 84 at any convenientpoint for supplying pumped fluid, such as fuel, to any suitable device(not shown) requiring the same.

Operation Fuel or other fluid to be pumped enters the central chamber 20via the inlet 80 from any suitable source (not shown). As the eccentric14 is rotated by the shaft 16 through one complete cycle, the high sideof the eccentric 14 will alternately abut against and then leave contactwith the striker plate 58 of the piston assembly 37, While the high sideof the eccentric 14 is in contact with the striker plate 58, the flangedmember 72 will be moved to the left in FIGURE 1 against the force of 3the spring 70, thereby also moving the diaphragm 28 to the left.

Since this is the suction stroke, the volume of the pumping chamber 24will be increased, causing the check valve 52 to leave its seat 54against the force of the spring 56 and permitting fuel to flow from thecentral chamber 20 into the pumping chamber 24. During this suctionstroke, the discharge check valve 62 will be held against its seat bythe combined forces of the spring 64 and the pressure of the fluid inand downstream of the discharge chamber 26. The pressure in thedischarge chamber 26 is maintained by virtue of the large spring 70 inthe central chamber 20 having urged the diaphragm 28 to the left, asjust described. This leftward movement of the diaphragm 28 not onlymaintains the pressure within the discharge and accumulator chambers 26and 22, respectively, but it also serves to supply the required flowthrough the conduits 84 and 86 to the equipment supplied by the pump.

Once the high side of the eccentric 14 leaves contact with the strikerplate 58, the springs 66 and 70 will begin to move the piston assembly37, and the diaphragm 30, to the right in FIGURE 1 on its pumpingstroke. The spring 66 is required in this particular embodiment becausethe areas of the diaphragms 28 and 30 are substantially equal so as tobe subjected to substantially equal forces. Obviously, if the diaphragm30 were smaller in area than the diaphragm 28, the spring 66 would notbe required since the spring '70 would, on its own, move the pistonassembly 37 to the right against the lesser force adjacent the smallerdiaphragm. In either event, the movement to the right will force thecheck valve 52 closed and the discharge check valve 62 open, against theforce of the relatively small spring 64, and discharge fluid out of thepumping chamber 24, into the discharge chamber 26 and through the outlet82 and thence through the conduit 84 to the supply conduit 86, as wellas to the accumulator chamber 22, thereby recharging the accumulatordiaphragm 28 until the washer 34 contacts the abutment 78.

FIGURE modification In the FIGURE 5 embodiment, all elements which aresimilar to corresponding elements in FIGURE I bear the same referencenumerals. The principal difference 'between FIGURES 5 and 1 is that thediaphragm 30 and piston assembly 37 of FIGURE 1 have been replaced by apiston assembly 92 that eliminates the need for a diaphragm similar tothe diaphragm 30 of FIGURE 1.

The piston assembly 92 includes an outer cylindrical member 94 havingopposing openings 96 formed therein for passage of the shaft 16. A pairof plates 98 and 100 are fixedly secured to the right end of thecylindrical member 94, as by screws 102, and are slida-bly fitted withinthe walls of the central chamber 20. The plate 100 is undercut toreceive a seal 104 which prevents leakage between the central chamber 20and the pumping chamber 24.

The left end of the piston assembly 92 includes a member 106 which issimilar in function to the striker plate 58 of FIGURE 1; however, member106 includes a pocket 108 suitable for receiving an extension 110 formedon a rocker arm 112. The rocker arm 112 is secured to a bushing 114, asby screws 116, the latter assembly being fitted around the usualeccentric 14. A resilient disk 118 may be fitted between the member 106and the end 120 of the cylindrical member 94 in order to help absorb anyshock resulting from the high side of the eccentric 14 causing theextension 110 to impact the bottom of the pocket 108.

It is obvious that the FIGURE 5 modification operates in the samegeneral manner as the FIGURE 1 embodiment; thus, a discussion of theoperation need not be repeated. It should be noted, however, that theFIGURE 5 embodiment does not include a spring 66, as illustrated inFIGURE 1, since the pumping area of the plate 100 of the piston assembly92 is considerably smaller than the area of the accumulator diaphragm28. Hence, as previously explained, the spring 70 will move the pistonassembly 92 to the right in FIGURE 5 during the pumping stroke,supplying output flow and recharging the accumulator.

FIGURE 6 modification A shock absorbing system 122 may be substitutedfor the resilient disk 118 arrangement illustrated in FIG- URE 5. Asillustrated in FIGURE 6, a resilient member 124 is confined between andsecurely fastened at its inner and outer surfaces to members 126 and 128which are equivalent to the members 106 and 120 of FIGURE 5.

It should be apparent that, as the extension is moved to the left intocontact with the bottom of the pocket 134) formed in the member 126 bythe eccentric 14, the member 126 will make its initial leftward movementbefore the member 128 is caused to move, due to the give in theinter-mediate resilient ring 124. Thus, the instantaneous inertia forceson the various pump assembly components are lower, tending to prolongthe life thereof; also, the instantaneous pressure increase on thediaphragm 28 is likewise lower, tending to reduce pressure pulsesthrough the conduits 84 and 86 to the equipment supplied by the pump. Ifdesired, the FIGURE 6 arrange-ment could be incorporated in the FIGURE 1structure merely by reworking the end 59 and striker plate 58 thereof.

Summary It should be readily apparent that, as compared to prior arteccentric driven pumps, the invention presents a novel dual approach inincreased pump life and decreased pressure surges or pulses downstreamof the pump. In other words, the use of the eccentric to actuate thesuction stroke and a spring to actuate the pumping strike will producesuch advantages. These advantages may be made even more pronounced bythe addition of the resilient means described in connection with FIGURE6.

While a preferred embodiment and two modifications have been shown anddescribed for purposes of illustration, other modifications may bepossible within the scope of the following claims What I claim as myinvention is:

1. A pump assembly, comprising a chamber including a shaft having aneccentric formed thereon, an inlet and an outlet, a pump element attimes being moved by said eccentric away from said outlet; anaccumulator chamber; a passageway communicating between said accumulatorchamber and said outlet; a pressure responsive device forming a movablewall between said first mentioned chamber and said accumulator chamber;and a spring mounted between said pressure responsive device and saidpump element for urging said pump element toward said outlet when saidpump element is not being moved by said eccentric.

2. A pump assembly, comprising a chamber including a shaft having aneccentric formed thereon, an inlet and an outlet, a pump element attimes being moved by said eccentric away from said outlet; anaccumulator chamber; a passageway communicating between said accumulatorchamber and said outlet; a pressure responsive de vice forming a movablewall between said first mentioned chamber and said accumulator chamber;and a spring mounted between said pressure responsive device and saidpump element 4 urging said pump element toward said oulet when said pumpelement is not being moved by said eccentric and for simultaneouslyurging said pressure responsive device away from said outlet so as tomaintain the pressure and flow downstream of said outlet.

3. The device is described in claim 2, wherein said pump element is adiaphragm assembly.

4. The device as described in claim 2, wherein said pump element is apiston assembly.

5. A pump assembly comprising a housing having first, second, third andfourth chambers formed therein, a shaft rotatably mounted through saidfirst chamber, an eccentric fixedly mounted on said shaft within saidfirst chamber, a first pressure responsive device forming a movable wallbetween said first and second chambers, a second pressure responsivedevice forming a movable wall between said first and third chambers, afirst spring-biased check valve between said third and fourth chambers,a second spring-biased check valve in said second pressure responsivedevice, a pump element slidably mounted in said first chamber andfixedly secured to said second pressure responsive device, and a springmounted between said pump element and said first pressure responsive device, said pump element at times being moved by said eccentric towardsaid first pressure responsive device against the force of said spring.

6. The device as described in claim 5, wherein said first and secondpressure responsive devices are diaphragm assemblies.

7. The device as described in claim wherein said first pressureresponsive device is a diaphragm assembly and said second pressureresponsive devices is a piston assembly 8. A pump assembly, comprising ahousing having first, second, third and fourth chambers formed therein;

a shaft rotatably mounted through said first housing; an eccentricfixedly mounted on said shaft within said first chamber; a firstpressure responsive device forming a movable wall between said first andsecond chambers; a second pressure responsive forming a movable wallbetween said first and third chambers; 21 first spring-biased checkvalve between said third and fourth chambers; a second spring-biasedcheck valve in said second pressure responsive device; a pump elementslidably mounted in said first chamber and fixedly secured to saidsecond pressure responsive device; a member in sliding contact with saideccentric; resilient means secured between said said member and saidpump element; and a spring mounted between said pump element and saidfirst pressure responsive device; said member, said resilient means andsaid pump element at times being moved by said eccentric toward saidfirst pressure responsive device against the force of said spring.

References fitetl by the Examiner UNITED STATES PATENTS 1,882,92810/1932 Rockwell 103224 2,359,960 10/1944 Anderson 103-150 3,120,8172/1964 Price 10 3-150 3,192,864 7/1965 Notte l03l50 LAURENCE V. EFNER,Primary Examiner.

1. A PUMP ASSEMBLY, COMPRISING A CHAMBER INCLUDING A SHAFT HAVING ANECCENTRIC FORMED THEREON, AN INLET AND AN OUTLET, A PUMP ELEMENT ATTIMES BEING MOVED BY SAID ECCENTRIC AWAY FROM SAID OUTLET; ANACCUMULATOR CHAMBER; A PASSAGEWAY COMMUNICATING BETWEEN SAID ACCUMULATORCHAMBER AND SAID OUTLET; A PRESSURE RESPONSIVE DEVICE FORMING A MOVABLEWALL BETWEEN SAID FIRST MENTIONED CHAMBER AND SAID ACCUMULATOR CHAMBER;AND A SPRING MOUNTED BETWEEN SAID PRESSURE RESPONSIVE DEVICE AND SAIDPUMP ELEMENT FOR URGING SAID PUMP ELEMENT TOWARD SAID OUTLET WHEN SAIDPUMP ELEMENT IS NOT BEING MOVED BY SAID ECCENTRIC.